Jar type well packer



y 6, 1952 c. c. BROWN ET AL 2,595,563

JAR TYPE WELL FACKER Filed Sept. 2, 1947 2 SHEETS-SHEET l JR. BASS ML 0.0. BROWN INVENTORJ ATTORNEY y 6, 1952 c. BROWN ET AL 2,595,563

JAR TYPE WELL PACKER Filed Sept. 2, 1947 4 2' SHEETS-SHEET 2 i -34 q as-3| J') /25 I ml J.R.BAS$ u. 0.0. BROWN INVENTORJ F G 3 ATTORNEYPatented May 6, 1952 JAR TYPE WELL PAGKER'.

Cicero C. Brown, Houston, and John R. Bass Brenham, Tex.; said. Bassassignor to said Brown Application September 2, 19.47. Serial no.771,752-

Claims- 1 This invention relates to. well packers and par.- ticularly topackers of the hook-Wall type adapted for use in deep wells. 7

At the great depths currently being attained in the drilling of oil andgas wells, the problems attendant upon the use of packers both fortesting purposes and for production purposes have been increasedgreatly, due primarily to the extremely high loads impressed upon thepackers in such deep wells, both by the great weight of the long stringsof pipe and by the hydrostatic pressure of the fluid columns normallypresent in such deep wells.

When hook-well packers of the more conven tional type are set in a wellunder such heavy.

loads, the toothed slips, which conventionally engage the wall of thewell casing, are driven so tightly into the metal of the well casingthat their subsequent reelase, when it is desired to remove the tubingor production string and packer from the well, is frequently verydifficult to accomplish. The packing element may likewise become sotightly compressed against the wall of the casing as to become almostbonded to the metal of the casing, with the result that great diflicultyis also frequently experienced in effecting its release. Thedifficultyis frequently accentuated by settling and deposit of sand and siltcarried by the well fluids on and around the packing and slip elements.

The problem of efficient setting and release of packers in such deepwells is particularly important in connection with the use of suchpackers as test packers, wherein repeated setting and release of thesame packer must be effected at several diiferent depths in a well forthe purposes of testing various portions of the casing for leaks and fortesting various elevations in the well for producing horizons. In suchoperations it becomes especially important that no great difficultyshould be experienced in the repeated setting and release of the packer,since otherwise great delay and severedamage or destruction of thepacker and damage to the well itself may result in many cases.

The packer in accordance with this invention combines the functions of amore or less conventional hook-wall packer, and a cooperating jarringmechanism of novel form and construction which is adapted to effect theready release of the packer under extreme load conditions at whichrelease of the packer cannot be effected with more conventionalstructures and methods without damage or destruction to the packerelements. The novel jarring mechanism is of a form which is adapted toemploy the high energy available in long pipe strings when under tensionto release. the packer structure.

Accordingly, a primary object of this invention is the provision of animproved packer structure for a use in deep wells which is readilyreleasable under heavy load conditions.

An important object of this invention is the provision of a hook-walltype packer which combines the functions of a packer and a novel jarmechanism for efficient and ready release of the packen.

A further object is the provision of a packer which is releasable byjarring action effected through relative rotary and longitudinalmovement of the pipe string on which the packer is mounted.

A more specific object is the provision of a hook-wall packer having arelease element for normally releasing the packer by relative vertical-movement of the supporting pipe string and which, by appropriateapplication of relative rotary movement, may be caused to produce asharp jarring action upon the packer elements so as to effect release ofthe casing engaging elements which do not release in response solely tothe normal vertical movements.

Other and more specific objects and advantages of this invention willbecome apparent from the following detailed description when read inconjunction with the accompanying drawings which illustrate one usefulembodiment in accordance with this invention.

Fig. 1 is an elevational view of the packer structure in accordance withthis invention show ing the position of the parts thereof, while thepacker is being inserted in a well casing;

Figs. 2 and 2a comprise an enlarged quartersectional-elevation of thepacker structure shown in Fig. l, which illustrates the positions of theseveral packer elements in a well casing prior to the setting of thepacker;

Figs. 3 and 3a comprise a view similar to Figs. 2 and 2a showing theposition of the pack-er elements when the packer is set in a wellcasing, and showing in broken lines the positions of some of the packerelements at the instant of release;

Fig. 4 is a cr0ss-sectional view along line 44 of Fig. 3a, looking:upwardly toward the upper end of the packer structure; and

Fig. 5 is a quarter-sectional elevation of a pertion of the packerstructure showing intermediate positions of some of the packer elementsduring the release movements thereof.

Generally speaking, and in accordance with an illustrative embodiment ofthis invention, the foregoing objects are accomplished by providing anovel inter-engaging means between the packer supporting body and theslip expanding mandrel by which torsional and tensional forces may bedeveloped in the supporting pipe which are automatically releasable toproduce sharp jarring impacts for transmission to both the slips and theconventional resilient sealing elements in a manner which will effecttheir release substantially simultaneously.

Referring to the drawings and particularly to Figs. 1, 2 and 2a, thereis shown a well casing II) in which has been inserted a packer structurein accordance with this invention, which is conventionally connectedinto a tubing or other pipe string (not shown), which is employed in theconventional manner to lower the packer structure into the well andprovides support for the same. The packer structure comprises a tubularbody, indicated generally by the letter B, composed of sections II, I2and I3 which are connected to form a part of the pipe string supportingthe packer structure. Sections I2 and I3 of the body are joined togetherby means of a threaded collar I4, the external diameter of which isgreater than that of the connected sections I2 and I 3, thereby formingan annular external shoulder I5 about the lower end portion of bodysection I2. Concentrically disposed about body section I2 is adownwardly tapering conica1 mandrel I6 which supports a plurality ofangularly spaced wickered slips ll of generally conventional shape,which are slidable on the surface of mandrel I6 in slots I8 andare heldtherein by a conventional dove-tail tongue-andgroove arrangementindicated at I9. Passage- 8 ways Ilia extend through the body of mandrelI8 and provide communication between the interior and exterior thereof.The upper end of mandrel I6 carries a vertically aligned group ofannular compressible sealing elements 28-20, constructed of rubber orrubber-like resilient materials, which are adapted to be expanded undercompression to seal the annular space between casing I0 and the tubularbody B. These sealing elements are of generally conventionalconstruction and are supported between a pair of ends screwed into endring 20b, thereby tying.

the sealing elements together into a unitary structure with mandrel I6.The upper edge of end ring 20b is ground to form an annular seat 28g,which cooperates with an annular valve member 20h carried by bodysection I I to close the annular space between the interior of thepacker structure and supporting body B when relative longitudinalmovement between the body B and the packer structure in setting thepacker brings annular valve 28h into contact with seat 20g. The lowerend of mandrel I6 is threaded internally for rigid connection thereto ofan elongated sleeve member 2| which concentrically surrounds bodysections I2 and I3 as well as coupling I 4. Sleeve member 2| iscounterbored from its lower end to provide an internal annular shoulder22, which is adapted for cooperation with shoulder I5 on coupling I4.The external diameter of sleeve member 2| is successively enlargedtoward its lower end to form vertically spaced external annularshoulders 23 and 24. Sleeve member 2| is provided with J-slots 2501diametrically opposite sides thereof (see Fig. 4), the longitudinal legsof the J-slots extending downwardly to the lower end of sleeve member2|. The hook portions of the J-slots are arranged so that they will beopposite substantially the mid-section of coupling I 4 when the packerstructure is in the unreleased position.

A longitudinal recess 25 is cut into the left hand wall of thelongitudinal portion of each of the J-slots '25 and extends upwardly toa point spaced below shoulder 24 of the sleeve member. The upper ends ofrecesses 26 are arranged to form upwardly sloping shoulders 21, theout-er ends of which terminate at the adjacent'edges of the relatedJ-slots.

Concentrically surrounding sleeve member 2| is a generally tubular slipcage 28, of generally conventional construction, to the upper end ofwhich slips I1 are pivotally connected by means of links 29. The outersurface of slip'cage 28 carries conventional bow springs 30 forfrictionally engaging the inner wall of casing Ill in the conventionalmanner. The lower portion of slip cage 28 is provided with a pair ofdiametrically opposed J-slots 3| which register with J-slots 25 ofsleeve member 2| However, the length-of slip cage 28 is less than thatof sleeve member 2| so that its lower end terminates just above shoulder24 of the'sleeve member. Slip cage 28 is provided internally thereof,adjacent its upper end, with an annular shoulder 32 which is adapted forcooperation with shoulder 23 on 'wardly at'angles complementingshoulders 27.

The above-described packer structure is operated in the followingmanner: Body B of the structure is connected into a tubing or other pipestring (not shown) in the conventional manner and lowered into casingI0. During this operation, the several elements of the packer structurewill be maintained in the positions shown particularly in Figs. 1, 2 and2a, through the locking engagement of J-pins 33 in the hook portions ofJ-slots 25 and 3|, thus allowing the packer structure to move freelydown the casing except for the frictional resistance resulting from thecontact of bow springs 30 with the inner wall of easing I0, thisresistance being, of course,

overcome by the weight of the packer structure and supporting pipestring in effecting the lowering of the packer structure through thecasing. At this stage annular valve member 2071. will be spaced fromend-ring 20b, thus leaving open the annular space between the packerstructure and the supporting body B and permitting the free passagethrough the structure of well fluids entering through passageway Ilia,to thereby further reduce the resistance to the downward movement of thepacker structure in the casing and to permit circulation of well fluidsthrough the wellin the conventional manner; when desired.

It-will be notedthat when the'packerstructure is in the locked orunreleased position, as illustrated in Figs. 1, 2 and 2a, shoulder [5 oncollar I4 is in engagement with internal shoulder 22 of sleeve member 2|and forms means for supporting sleeve member 2! and itsconnectedmandrel-and packer elements on body 13 of the structure. At the sametime, external shoulder 23 on sleeve member 2! is in engagement withinternal shoulder32 of cage 23.-

When. the locked structure has been lowered to the point in the casing"at which it is to rotate body Bin like manner, while the frictionalcontact'ofbow spring 30 with the wall of easing It] will hold the packerstructure stationary to thereby permit this relative rotationalmovement. J-pins 33, being an integral part of body B, will move out ofthe hook portion of J-slots 25 and 3| in response to this relativerotational movement and will enter the vertical legs of the J-slots.Thereupon, the pipe string will be lowered'at the top of the well,lowering body B relative to the surrounding packer structure andallowing J-pins 33 to descend through the vertical legs of the J-slots.As the supporting body B is thus lowered, sleeve member 2| carryingmandrel it; and the sealing elements carried thereby, being supported oncollar l4, will also move downwardly. The downward movement of themandrel relative to slips l1 and slip cage 28 will expand the slips intoengagement with the casing wall. The engagement of the slipswith thecasing wall will stop the further downward movement of mandrel l6,sleeve member 2| and the sealing elements 20, but the lowering of thepipe string will be'continued until annular valve h contacts seat 20g,closing the annular space between the packer structure and body B andtransferring the weight of the string upon sealing elements 2i!2t. Underthe pressure exerted by the weight of the pipe string, the sealingelements will expand and seal the annular space between the exterior ofthe packer structure and casing l0. At the same time, pressure will alsobe exerted against the upper end of mandrel l6 causing the latter todrive slips l1 into very tight gripping engagement with the wall ofcasing 10 and thereby completing the setting of the packer structure.The continued downward movement of body B in completing the setting ofthe packer will bring J-pins 33 to a position in the J-slots oppositerecesses 26 and below sloping shoulders 21. The position of the severalelements of the packer structure, when the packer has been set, is shownin full lines in Figs. 3' and 3:1. It will be noted that shoulder 23 isnow spaced somewhat below shoulder 32 while shoulder l5 has moved aconsiderably greater distance below shoulder 22.

With the packer structure thus set, the desired testing on otheroperations may be now conducted in the conventional manner, the packerstructure remaining as described until the completion of suchoperations.

To release the packer for withdrawal from the well, under conditionswhere no unusual sticking ofthe slips and sealing elements has occurred,an upward pull is taken at the top of the well on the pipe stringsupporting body B. This will first lift valve 20h off of end ring 201),relieving the. pa'cker' structure of:the' weight of the pipe string.Continued upward movement of the pipe string will bring shoulder [5 intocontact with shoulder 22 and this engagement will force sleeve member 2|and mandrel I6 upwardly relative to slips I? which, by their slidingengagement with mandrel l 5 will be retracted thereby, thus pulling themout of engagement with casing i6. At the same time, the release ofpressure upon sealing elements 20-20 will permit them to return to theircontracted form while the upward force exerted against the mandrelthrough the engagement of shoulder 15 with shoulder 22 will aid inreleasing the sealing elements from their engagement with the casingwall. Finally, continued upward movement of the supportingpipe stringwill pull the entire packer structure upwardly out of the casing. Itwill be noted that under conditions where no special difficulty isencountered in releasing the packer structure, no rotational movementsor any movements other than direct upward pull on the supporting pipestring are required in order to effectively release the packer.

Where sticking of the slips and sealing elements is not excessive butsufficient to resist release solely through the upward pull on thesupporting pipe string as described, some degree of jarring may beaccomplished by merely lowering the pipe string and bringing it upquickly. The relatively quick sequential impacts of shoulder i5 uponshoulder 22 and of shoulder 23 upon shoulder 32 may be suificient toeffect release of the packing elements and the slips, although the forceavailable for producing the desired degree of shock is necessarilylimited because of the inertia of the pipe string which is inherent in adirect upward pullon the usually very long pipe strings.

However, packers of the general type described frequently become sotightly stuck in the casing that the relatively simple release movementspreviously described will be ineffective to release the packer andpermit its withdrawal from the well. Under such circumstances, thepacker structure in accordance with the present invention possessescertain novel features of construction by which high energy jarringimpacts may be applied to the'packer structure during release movements,which will effect relatively quick and efficient release of the packerstructure in a manner to be described hereinafter.

When such difficult release conditions are encountered, the paclrerstructure being set and the parts thereof in the relative positionsshown in full lines in Figs. 3 and 3a, the supporting pipe string willbe rotated at the top of the well in the clockwise or right-handdirections which will cause J-pins 33 to enter recesses 26 until theforward faces of the J-pins engage the inner walls of the recesses.While the actual degree of rotation required to effect this engagementis relatively small at the point of engagement, the natural flexibilityof the long string of pipe to which the packer is normally connectedwill necessarily require that several turns of the pipe string be madeat the top of the well to produce the small rotary movement required formoving J-pin 33 into recess 25. For example, in a string of 'pipeseveral thousand feet long, about two full turns will be required at thetop of the Well. This twisting of the long pipe string will introduce aconsiderable degree of torque into the pipe string which will cause thepipe string to unwind or-rotate in the opposite direction when thetorque-creating force is released at the top of the well.

force to the pipe string against the resistance created through theengagement of J-pins 33 with shoulders 21 will produce a reaction offorces at these contacting faces, the resultant of which will begenerally rearwardly in the plane of the contacting faces and willproduce a camming action between thefaces soas to force J-' pins 33 toslide rearwardly off of shoulders 21 and into the vertical legs ofJ-slots 25. This action will produce a quick release of the tension inthe pipe string which, due to its resiliency, will cause body B to jumpsharply upwardly relative to sleeve member 2| and by virtue of thissudden release of the large amount of energy available in the stretchedpipe string, will drive shoulder l5 up against shoulder 22 (see Fig. 5)with a sharp, high-energy impact which will be transmitted throughsleeve member 2| to mandrel l6 and sealing elements 26-48 and will jarthese elements sharply in the upward direction as is required to effecttheir release. This impact will be followed almost instan taneously by asimilar sharp impact of shoulder 23 striking shoulder 32 which willsimilarly sharplyjar slip cage 28 and slips I! to aid in effecting theirrelease from the casing. These inter-engaging parts are so dimensionedthat the impacts between shoulder l5 and sleeve member 2| and betweensleeve member 2! and slip cage 28 follow in very close succession suchthat the force of the original impact is transmitted almostinstantaneously both to mandrel l6, slip cage 28 and slips I1, wherebyall of these elements will be caused to move in a releasing directionpractically simultaneously. Since mandrel IE will be moving upwardlyunder the force of the initial impact, it will place a retractive pullupon slips H and the closely following second impact directly upon theslip cage will cause the latter and the slips to move upwardlysubstantially in unison with the mandrel whereby both sets of elementswhich were in engagement with the casing will thus be released anddriven upwardly substantially together.

1 If the first jar fails to release the packer, the jarring operationmay be repeated as many times as may be found necessary to free thepacker. Each repetition of the jarring action is simply accomplished bylowering the supporting pipe string at the top of the well, rotating itto the right, and taking an upward strain again thereon in the mannerdescribed.

By means of the described apparatus, the great amount of energyavailable in a twisted and stretched supporting pipe string,particularly in deep wells requiring long strings of pipe, is caused tobe released quickly and transmitted with full effect in the sharpimpacts which will be applied substantially simultaneously against theportions of the packer structure which are engaged with the casing toeffect their release.

In the ordinary case, only a very few turns of the upper end of the pipestring at the top of the well, followed by a relatively small up- .-wardstrain is all that is necessary to produce the jarring movementsdescribed and thus release of the packer structure may be effectedquickly and effectively with a minimum of effort even in cases of severesticking of the structure.

Various alterations and modifications may be made in the details of thisinvention within the scope of the appended claims but without departingfrom the spirit of this invention.

What we claim and desire to secure by Letters Patent is:

1. A well packer including a tubular body member supporting for relativemovement thereon a sealing element, a s1ip cage, slips hingedlyconnected to said cage, a slip-expanding member connected to saidsealing element movable into and out of expansive-relation with saidslips in response to relative longitudinal movement between saidmembers, opposed jarring shoulders carried by said members engageableupon relative longitudinal movement between said members, and opposedabutment elements carried by said members longitudinally spaced fromsaid shoulders and positioned to be engaged in advance of engagement ofsaid shoulders upon relative longitudinal movement and upon limitedrelative rotation of said members, said abutment elements havingcam-shaped engaging surfaces shaped to slide past each other to effectsudden release therebetween upon application to one of said members ofan axially directed engaging force exceeding the resistance of theengaged abutment elements to such release.

2. A well packer including a tubular body member supporting for relativemovement thereon a sealing element, a slip cage, slips hingedlyconnected to said cage, a slip-expanding member connected to saidsealing element movable into and out of expansive relation with saidslips in response to relative longitudinal movement between saidmembers, opposed jarring shoulders carried by said members engageableupon relative longitudinal movement between said members, and opposedabutment elements carried by said members longitudinally spaced fromsaid shoulders and positioned to be engaged in advance of engagement ofsaid shoulders upon relative longitudinal movement and upon limitedrelative rotation of said members, said abutment elements havingengaging surfaces inclined at an angle to the longitudinal axis of saidmembers.

3. A well packer including a tubular body member supporting for relativemovement thereon a sealing element, a slip cage, slips hingedlyconnected to said cage, a slip-expanding member connected to saidsealing element movable into and out of expansive relation with saidslips in response to relative longitudinal movement between saidmembers, an extension sleeve rigidly connected to said slip-expandingmember concentrically interposed between said slip cage and said bodymember, opposed jarring shoulders mounted on said sleeve and said bodymember engageable upon relative longitudinal movement between saidsleeve and said body member, and opposed abutment elements mounted onsaid sleeve and said body member longitudinally spaced from saidshoulder and positioned to be engaged in advance of engagement of saidshoulders upon relative longitudinal movement and upon limited relativerotation between said sleeve and said body member, said abutmentelements having engaging surfaces upwardly inclined at an angle; to thelongitudinal axis of said sleeve,

mb dy m mb A. well, a e nc u ng a tubular body member supporting forrelative movement thereon a sealing element, a slip cage, slips hingedlyconnected to said cage, a slip-expanding member connected to saidsealing element movable into; and out of expansive relation with saidslips in response to relative longitudinal movement e e sai rs an exteon Sleeve g d connected to said slip-expanding member concentricallyinterposed between said slip cage and said body member, a first pair ofopposed jarring shoulders mounted on said body member and said sleeve, asecond pair of jarring shoulders mounted on said sleeve and said slipcage and axially spaced from said first pair, said pairs beingpositioned for sequential engagement in response to upward movement ofsaid body member relative to said sleeve member and said slip cage, andopposed abutment elements mounted on said sleeve and said body memberlongitudinally spaced from both said pairs of shoulders and positionedto be engaged in advance of engagement of both said pairs of shouldersupon relative longitudinal movement and upon limited relative rotationbetween said sleeve and said body member, said abutment elements havingengaging surfaces upwardly inclined at an angle to the longitudinal axisof said sleeve and body member.

5. A well packer including a tubular body member supportin for relativemovement thereon a sealing element, a slip cage, slips hingedlyconnected to said cage, a slip-expanding member connected to saidsealing element movable into and out of expansive relation with saidslips in response to relative longitudinal movement between saidmembers, an extension sleeve rigidly connected to said slip-expandingmember concentrically interposed between said slip cage and said bodymember, opposed jarring shoulders mounted on said sleeve and said bodymember engageable upon relative longitudinal movement between saidsleeve and said body member, a longitudinal slot in said sleeve, a pinon said body member extending into said slot, and an abutment at oneside of said slot longitudinally spaced from said shoulders andpositioned to be engaged by said pin in advance of engagement of saidshoulders upon relative longitudinal movement and upon limited relativerotation of said members, the pin-engaging surface of said abutmentinclining upwardly into said slot.

6. In a well packer including a tubular body .1

member supporting for relative movement thereon a tubular packer membercarrying expandible elements for engaging a well wall, a jarringmechanism for effecting release of said packer member from said wellwall comprising, opposed jarring shoulders carried by said membersengageable upon relative longitudinal movement between said members, andopposed abutment elements carried by said members longitudinally spacedfrom said shoulders and in position to be engaged in advance ofengagement of said shoulders upon relative longitudinal movement andupon limited relative rotation of said members, said abtument elementshaving relatively slidable cam-shaped engaging surfaces shaped to causesaid abutment elements to be forced past each other longitudinally toeffect sudden release therebetween when the axially directed forceapplied to one of said members in effective engagement of said abutmentelements exceeds the re- 10 sistance of the engaged abutment elements tosuch release.

7. In a well: packer including a tubular body member supporting forrelative movement thereon a tubular packer member carrying expandibleelements for engaging a well wall, a jarring mechanism for effectingrelease of said packer member from said well wall comprisin opposedjarring shoulders carried by said members engageable upon relativelongitudinal movement between said members, and opposed abutment elentca r ed, by S i membe longitudinally spaced from said shoulders and inposition to be engaged in advance of engagement of said shoulders uponrelative longitudinal movement and upon limited rotation of saidmembers, said abutment elements having relatively slidable engagingsurfaces inclined at an angle to the longitudinal axis of said members.

8. In a well packer including a tubular body member supporting forrelative movement thereon a tubular packer member carrying expandibleelements for engaging a well wall, a jarring mechanism for effectingrelease of said packing member from said well Wall comprising, opposedjarring shoulders carried by said members engageable upon relativelongitudinal movement between said members, a longitudinal slot on oneof said members, a pin on the other of said members extending into saidslot, and an abutment at one side of said slot longitudinally spacedfrom said shoulders and positioned to be engaged by said pin in advanceof engagement of said shoulders upon relative longitudinal movement andupon limited relative rotation of said members, the pin-engaging surfaceof said abutment inclining upwardly into said slot.

9. In a well packer including a tubular body member supporting forrelative movement thereon a tubular packer member carrying expandibleelements for engaging a well wall, a jarring mechanism for effectingrelease of said packer member from said well wall, comprising, opposedjarring shoulders carried by said members engageable upon relativelongitudinal movement between said members, a longitudinal slot on oneof said members, a pin on the other of said members extending into saidslot, an abutment at one side of said slot longitudinally spaced fromsaidshoulders and positioned to be engaged by said pin in advance ofengagement of said shoulders upon relative longitudinal movement andupon limited relative rotation of said members, the pin-engaging surfaceof said abutment inclining upwardly into said slot, and a pin-receivingrecess in the side of said slot opposite said abutment.

10. In a well packer including a tubular body member supporting forrelative movement thereon a tubular packer member carrying expandibleelements for engaging a well wall, a jarring mechanism for effectingrelease of said packer member from said well wall comprising, opposedjarring shoulders carried by said members engageable upon relativelongitudinal movement between said members, a longitudinal slot in oneof said members, a pin on the other of said members extending into saidslot, an abutment at one side of said slot longitudinally spaced fromsaid shoulders and positioned to be engaged by said pin in advance ofengagement of said shoulders upon relative longitudinal movement andupon limited relative rotation of said members, said abutment and saidpin having relatively slidable 11 engaging surfaces'inclining upwardlytoward said Number slot. 2,136,047 CICERO C. BROWN. 2,138,157 JOHN R.BASS. 2,182,549 5 2,187,482 REFERENCES CITED 2,21 ,353 The followingreferences are of record in the 2-363'400 file of this patent: 1 UNITEDSTATES PATENTS 2389869 2,426,370 Number Name Date 2,430, 23

1,785,277 Mack Dec. 16, 1930 12 Name Date Fulkerson Nov. 8, 1938Halliburton Nov. 29, 1938 Brumbly Dec. 5, 1939 Baker et a1 Jan. 16, 1940Spencer Oct. 1, 1940 Baker Jan. 30, 1945 Quintrell July 31, 1945- PhippsNov. 27, 1945 Penick Aug. 26, 1947 Taylor et a1 Nov. 11, 1947

